The broad goals of this research are to further develop capillary electrophoresis (CE) as an analytical technique to study the physicochemical properties of the glycopeptide antibiotics vancomycin (Van), ristocetin (Ris), and teicoplanin (Tei) and their derivatives. Its focus is on demonstrating principles and developing useful analytical techniques that can be applied to the analysis of receptor-ligand interactions and microscale reactions. The development of resistance to antibacterial agents is a worldwide problem that continues to compromise the clinical effectiveness of new drugs used in the treatment of many infectious diseases. Hence, studies probing the physicochemical properties of these antibiotics via chemical modification are needed. In the proposed research two specific CE techniques will be: on-column microreactor techniques and affinity capillary electrophoresis (ACE). Techniques utilized in this study include chemical modification and characterization, chemical separation and identification of small molecules by CE utilizing both laser-induced fluorescence (LIF) and ultraviolet/visible (UV/VIS) detection schemes and high-performance liquid chromatography (HPLC). The research will develop new bioanalytical techniques and will focus on examining small biomolecules involved in the prevention of disease and, hence, to the issue of public health. This understanding will strengthen the scientific base underlying the design, preparation, and application of CE towards a host of health-related problems. The specific aims of the research are to I. Couple On-Column Linked Antibiotic Derivatization Reactions to ACE. II. Examine On-Column Ligand Derivatization Reactions Coupled to ACE. III. Utilize Multiple-Injection ACE (MIACE) to Analyze the Binding of Ligands to Glycopeptide Antibiotics. IV. Optimize Conditions for Flow-Through Partial-Filling ACE (FTPFACE) to Analyze the Binding of Ligands to Antibiotics. The proposed research will: Demonstrate the versatility of CE in determining physicochemical parameters of antibiotics; Demonstrate high-throughput derivatization of receptors and ligarids coupled to ACE; Provide for rapid synthesis and accurate analysis of drug targets; require reduced samples volumes compared to other analytical techniques and; reduce sample waste and disposal.